There's some good recipes, but not so well explanation about what they do in deep (you need a basic WebDriver knowledge to read this book in some recipe, in my opinion).
There's a recipe which refers the use of a object repository, and it's is well know of old automation tools couldn't map element in a effective way.
There's some recipes not related to WebDriver, like comparing two screenshots or few related like create an element to handle jQuery Tabs (!), Performance testing with WebDriver (!), Testing HTML5 Web Applications that is a lot of workarrounds using javascript
So the book is ok, there's a good introduction but, in my opinion, the authors try to turn WebDriver in the same way as a commercial tool (with a lot of "custom features" that not always will help).
And they missed one of most important subject in WebDriver nowadays: RemoteDriver and Grid